I have a 94 z28 auto with a cc306 cam. The problem is when it warms up it makes a popping sound from the exhaust then dies. Then when i try to start it up it is hard to turn over. If I let it cool down for an hour or two it will turn over fine. Any idea what is wrong here???

 

I would get it scanned for codes as it may isolate problem.. usually mechanical failures don't come and go w/heat. my upfront guess is spark since it pops, could be ICM as they are very prone to fail when hot on these cars, coil, or opti. When you say hard to turn over do you mean it cranks slow, that could be low voltage, weak battery or weak starter. Low voltage can cause ignition failures do you have 12V + at the coil/ICM when running ? here's some things to check when it dies and won't start :ref shoebox http://shbox.com/1/4th_gen_tech2.html#opti_test

 

Its really weird its like the starter does not have the power to turn it over fast. But after i let the car cool down it turns over fine so the battery is fine. The starter is only 6 months old.

 

Excessive resistance in your wires and alternator cable can increase under heat. With your car running watch the voltage on the alternater to ensure you're making 13.5-14.5v. Also the try putting an AC multimeter on the battery to ensure you're getting no more than 50 mvAC as the rectifier bridge in the alternator can act up under heat as well. Most cars don't run happily if they drop below about 11.6v running.